Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

1995 z28 obdII or obdI?

Old Jan 22, 2010 | 07:09 PM
  #1  
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1995 z28 obdII or obdI?

Why am i seeing mixed opinions on 95 z28's being obII? I was told it was obd1. But i seen where GM put obdII in some cars before 96. Like here for instance: http://www.obdii.com/connector.html

If you scroll down you will see something about it.
Old Jan 22, 2010 | 09:19 PM
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Here's the GM list of OBDII '95 engines.

http://service.gm.com/gmspo/mode6/index.html
Old Jan 22, 2010 | 10:13 PM
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Originally Posted by mrl510
Why am i seeing mixed opinions on 95 z28's being obII? I was told it was obd1. But i seen where GM put obdII in some cars before 96. Like here for instance: http://www.obdii.com/connector.html

If you scroll down you will see something about it.
Why? I guess it is because people are misinformed.

Originally Posted by shbox.com
The only 1995 f-body engine that is OBD-II is the 3.8L V6 that came out during the model year (replacing the 3.4L V6 that was OBD-I).
Old Jan 23, 2010 | 08:23 AM
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Originally Posted by mrl510
Why am i seeing mixed opinions on 95 z28's being obII? I was told it was obd1. But i seen where GM put obdII in some cars before 96. Like here for instance: http://www.obdii.com/connector.html

If you scroll down you will see something about it.
I think you are mistaking that just because some 95 vehicles have the OBD2 style connector that it is running an OBD2 PCM. The only 95 F-body that came with the OBD2 PCM is the 3.8L V6. All 95 LT1 F-bodys have the OBD2 style connector, but are still using the OBD1 PCM.

Last edited by DOOM Master; Jan 24, 2010 at 11:17 AM. Reason: forgot to add 95
Old Jan 23, 2010 | 10:44 AM
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Originally Posted by DOOM Master
All LT1 F-bodys have the OBD2 style connector, but are still using the OBD1 PCM.
Lets get this straightened out before more information is given out that is not necessarily correct.

93 LT1 - EPROM OBDI

94 LT1 - OBDI connector and OBDI PCM

95 LT1 - OBDII connector and OBDI PCM - this is why many auto parts stores cannot scan 95LT1 pcm's for error codes. They don't know what they are really working with.

96-97 LT1 - OBDII connector and OBDII PCM

That's the LT1 line-up for you. The smaller v6 engines I cannot reference for you at this time.

Last edited by Airbornec507; Jan 24, 2010 at 05:03 PM. Reason: Excellent...now all the info makes sense.
Old Jan 24, 2010 | 11:20 AM
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Originally Posted by Airbornec507
Lets get this straightened out before more information is given out that is not necessarily correct.
The post was only in reference to 1995 vehicles, but I can see how it might be taken incorrectly. I edited it to make sure there is no mistake it is for 95 vehicles.


Originally Posted by Airbornec507
93 LT1 - Flash pcm

94 LT1 - OBDI connector and OBDI PCM

95 LT1 - OBDII connector and OBDI PCM - this is why many auto parts stores cannot scan 95LT1 pcm's for error codes. They don't know what they are really working with.

96-97 LT1 - OBDII connector and OBDII PCM

That's the LT1 line-up for you. The smaller v6 engines I cannot reference for you at this time.
Also, the 93 ECM is not a FLASH-based ECM, it is an EPROM based one.
Old Jan 24, 2010 | 11:23 AM
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Originally Posted by DOOM Master

Also, the 93 ECM is not a FLASH-based ECM, it is an EPROM based one.
And its OBD-I.
Old Jan 24, 2010 | 05:05 PM
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Originally Posted by DOOM Master
The post was only in reference to 1995 vehicles, but I can see how it might be taken incorrectly. I edited it to make sure there is no mistake it is for 95 vehicles.




Also, the 93 ECM is not a FLASH-based ECM, it is an EPROM based one.
Excellent.....I'm glad both our posts make sense now.
Old Apr 19, 2023 | 02:04 AM
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Re: 1995 z28 obdII or obdI?

So is there a reader out there for one then? Cause I got a 95 z28 and it has the obd2 port. And I was there for like 5 mins looking dumb wondering why the car md thing I found in my house was throwing a reading error 😂
Old Apr 19, 2023 | 09:07 AM
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Re: 1995 z28 obdII or obdI?

There are dual-capability (OBD-1/OBD-2) scanners available. Typically come with correct cables. A used older OBD-1 (only) scanner will work, requiring either an adapter connector for the 16-pin connector, or you can use jumper wires, as shown on the Shoebox site:

http://shbox.com/1/xraycable.jpg

Avoid scanners made by Equus and Innova. Their LT1 database is incorrect and will typically return seven false/non-existent codes.

Avoid the Actron CP9001. It is just a box with a switch that shorts the DLC pins to flash the codes on the check engine light. 93 was the last year that will work.

Or, download free Scan9495 software, written specifically for the 1993-1995 LT1. You just need to have a PC and buy a cable:

https://www.camaroz28.com/forums/com...95-lt1-874306/
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